This invention relates to dicyanomethylene (DCM) based polymer dies and their production. These polymer dyes are used as red-emitting layers in organic optical components, in particular in light-emitting diodes.
Organic luminescence displays and diodes can be produced on the basis of low-molecular weight compounds which are transformed into light-emitting layers by technically relatively complex evaporation coating processes. As a rule it is possible to set the wavelength of the light emitted by dosing the light-emitting layers with certain fluorescence dyes. For example, U.S. Pat. No. 6,048,630 describes saturated red emitting OLEDs that are obtained by dosing Alq3 with special porphine derivatives. For these materials, a strong emission is found at approximately 650 nm. U.S. Pat. No. 5,409,783 teaches magnesium phthalocyanine for dosing of Alq3 for red-emitting luminescence displays. A strong emission is found at 692 nm.
The electroluminescence device has the following structure:    1. Transparent anode made of ITO coated glass    2. Hole injection layer of Cu phthalocyanine (100 Å)    3. Hole transport layer of poly-n-vinyl carbazole (600 Å)    4. Emission layer of Alq3 dosed with magnesium phthalocyanine    5. Electron transport layer of Alq3     6. Cathode of Mg/ag (2000 Å).
The complete device structure is created by deposition processes. U.S. Pat. No. 5,908,581 describes the use of special laser dyes having the general structure
for the dosing of the Alq3 emission layer. The emission maximum is at 616 nm. In addition to the complex technology of the construction of the device, the stability of such dosed emission layers must be viewed critically. As a result of migration processes of the dosing agent or aggregation, there can be a shift of the emission spectrum. Therefore organic LEDs based on conjugated polymers have several advantages. On one hand, these polymers, with suitable structural variations, can be deposited from solution directly in the form of thin films by spin-coating or dip-coating. On the other hand, the active structure is essentially immobilized with regard to migration and aggregation by the bond to a polymer main chain.
Therefore, light-emitting LEDs with different emission wavelengths have been developed. In addition to blue and green shades, it became possible using alkoxy-substituted PPV derivatives (MEH-PPV) to realize wavelengths of 615 nm (DE 196 52 261). Wavelengths>650 nm have not up to now been achieved by conjugated polymers.
Given these disadvantages of the prior art, the object of the invention is to make available polymer dyes, the emission maximum of which is in the red area of the spectrum. These materials must also be easy to process.